Generally, an electronic device, such as a mobile phone, uses a speaker as a sound generator.
Typically, a related micro-speaker has a case defining a sound hole, a frame attached to the case for forming a chamber, a magnetic circuit defining a magnetic gap, a diaphragm located in the chamber, and a voice coil attached to the diaphragm. While electrified, the voice coil will be activated to vibrate by the Lorenz Force and further drives the diaphragm to vibrate, which converts the electrical signals to sound waves. The diaphragm needs sufficient space to vibrate for ensuring good acoustic performance. However, as the trend of the volume of the speaker is smaller and smaller, space provided for the diaphragm to vibrate is accordingly reduced and limited.